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1. Field of the Invention
The present invention relates generally to safety devices used in fall protection, and, more particularly, to lanyard apparatus for use in providing fall protection for a load in an elevated environment.
2. Description of the Background Art
There are a number of basic devices, such as safety harnesses, for use in providing fall protection for loads in elevated environments, such as loads in connection with human external load operations (xe2x80x9cHELxe2x80x9d). Safety harnesses, for example, commonly consist of shoulder straps attached to a waist or chest belt. Some harnesses incorporate suspender-style straps with a tether point-of-attachment on the front center of the chest/waist strap. Others comprise a Y-shaped design, where the shoulder straps are connected to a strap extending vertically from the waist belt to form a three-point intersection. These harnesses are typically constructed of nylon webbing, and commonly include padding. The harness is designed to support the load (i.e., body weight) by the torso and shoulders of the user for suspension from a helicopter. Sit harnesses comprise another category of HEL devices. Also known as pelvic harnesses, bosun""s seat, rescue harnesses, or rigger""s harnesses, these devices suspend the user in a seated posture. The basic design of a sit harness includes a waist belt connected to leg loops routed around the top of the thighs. The point of the tether attachment typically extends directly in front of the upper pelvic region. Full-body harnesses (xe2x80x9cFBHxe2x80x9d) comprise a combination of sit harnesses and chest harnesses. While there are a number of variations of the basic design of the harness, all full-body harnesses include leg loops, shoulder straps, and either a waist belt, a chest belt, or both.
One application wherein such safety devices are used involves the use of rotary winged aircraft, such as helicopters, in external load transfer operations. For example, human external load operations typically involve the transportation of a passenger suspended by a cable assembly under a helicopter. For example, helicopters equipped with load suspension points, or hooks, are commonly used to transport loads in a sling configuration wherein the load is suspended beneath the helicopter by a suspension apparatus. In other applications, helicopters carry cargo as well as human loads in various configurations external to the fuselage, such as on the skids or on skid-mounted platforms. For example, load-bearing platforms may be affixed to the helicopter to permit persons to operate external to the crew compartment. In other situations, a person may stand on one of the helicopter landing skids and operate in the external environment. HEL operations are commonly performed in transmission line maintenance and repair procedures in the electrical power industry, in the logging industry to access remote work sites, and for emergency rescue operations.
The present inventor has contributed significantly to safety advances in helicopter external load operations, particularly external human load operations. My U.S. Pat. No. 4,673,059 discloses a method and system for placing a load, which may consist of a combination of personnel and equipment, on or in proximity to components of an energized power transmission line. My U.S. Pat. No. 5,417,304 discloses a method for suspending a load from a rotary winged aircraft, such as a helicopter, using an apparatus that incorporates an emergency release capable of being activated by the suspended person.
In certain situations, however, it is necessary or desirable to transfer external loads from a hovering helicopter to a structure, such as a power transmission tower or an energized or de-energized power transmission line, ground wire, or other elevated point or structure. Neither the methods disclosed in my ""059 and ""034 patents, nor the background art, discloses a suitable safety apparatus for accomplishing the transfer of an external load from a hovering helicopter to an elevated structure while maintaining adequate safeguards for both the helicopter as well as the load.
While my ""304 patent discloses an emergency release for use with a suspended load, the system disclosed therein is a release-on-command type system that requires the suspended person to: (1) realize the existence of an emergency effecting the helicopter; and (2) manually activate the quick release to permit the helicopter to pull away. If the suspended person fails to either realize an emergency situation requiring emergency release, or fails to activate the quick release that system will not adequately protect both the person and the helicopter. Thus, the primary concerns in such external load transfer applications involve maintaining adequate fall protection for the person or load during the transfer procedure without limiting helicopter operations, particularly the ability of the helicopter to execute emergency maneuvers and operations. It is critical to maintain full fall protection for the person or load through the entire transfer process, while at the same not limiting the operation of the helicopter in emergency situations.
Currently, there is little standardization and a general lack of safety procedures practiced by those performing HEL operations. While regulations exist regarding the physical and structural characteristics of external load operations, little consideration has been given to the issue of humans as external loads. Federal Aviation Regulations applicable to rotorcraft operations, particularly those referring to human external loads, are found in Title 14 of the Code of Federal Regulations (CFR). The collection of FAA regulations found in 14 CFR is often referred to as the Federal Aviation Regulations (FARs). Within 14 CFR, part 133 pertains directly to rotorcraft external load operations and contains subparts that address applicability, certification rules, operating rules, and related requirements. In addition, part 27 requires that any external load attaching means must include a quick-release system to enable the pilot to release the external load quickly during flight. While the regulations address a number of areas, they provide no specific detail regarding the attachment method, human load transfer methods, or the structure or function of quick-release devices.
As a result of the lack of adequate safety methods there have been a number of rotorcraft accidents in connection with HEL operations. During the period from 1973 through 1995, it has been reported that there were 473 external load operations in which the helicopters were involved in either an accident or an incident. Of the 473 accidents listed, a substantial number involved operations using a sling line or sling load. Accordingly, it is recognized that the predominant cause of external load accidents involves problems with the sling line/load.
One common, yet inherently risky prior art method of transferring an external human load from a hovering helicopter to a structure, in a non-sling configuration, consists of bringing the helicopter to a hover immediately adjacent to a structure, wherein the helicopter may be stabilized by the placement of one or both skids (or wheels) on the structure for a period of time thereby allowing the person to step from the helicopter to the structure. This method, however, is significantly flawed in that, to avoid tethering the helicopter to the structure and thereby limiting the availability of emergency flight procedures (e.g. emergency pull-away), there exist periods of time during the transfer that the person is without fall protection, and consequently at substantial risk. For example, a person transferring from a helicopter to a tower typically detaches a safety lanyard from a secure point on the helicopter and attaches the safety lanyard to the tower during the transfer process. Thus, there exists a period of time, between detachment and re-attachment, that the person is without fall protection. If, during this time period, the helicopter executes an emergency pull-away maneuver, the person is at substantial risk of falling.
Thus, although HEL operations have been practiced, there remains a need a safety lanyard apparatus for use in providing fall protection for loads in an external environment. More particularly there exists a need for an improved safety lanyard for use in external load operations that is adapted to provide total fall protection for the load while preserving emergency operating procedures for the helicopter by incorporating an automatically activating emergency quick release.
The present invention addresses the shortcomings of the background art by providing a fall protection lanyard apparatus for use in transferring loads in an elevated environment. The fall protection lanyard may be connected to a load and used to transfer the load from an airborne rotorcraft to a structure while providing fall protection and automatic emergency release capabilities to enable the rotorcraft to freely execute emergency maneuvers. A significant aspect of the invention relates to a lanyard apparatus that provides total fall protection for the load throughout the transfer process without restricting or otherwise limiting available emergency flight options/maneuvers by incorporating an emergency release that automatically activates on demand.
In a preferred embodiment, the fall protection lanyard apparatus includes first and second load-bearing lanyards, each terminating in a free end incorporating a hook or carabiner. The competing concerns of fall protection (for the load) and on-demand emergency release (for the aircraft) are each enabled by providing a quick release mechanism activated by a predetermined tension force, such as the force that would be experience if the first and second lanyards were simultaneously connected to the helicopter and a rigid structure and the helicopter executed an emergency pull-away thereby placing tension on the lanyard apparatus.
Each lanyard is preferably attached to a common point, such as a load bearing steel O-ring, which in turn is attached to a safety harness which secures the load. In one embodiment: the first lanyard incorporates a quick-release mechanism, which, upon activation, results in the separation of the hook end portion thereof; and the second lanyard incorporates a limited slip mechanism, which, upon application of a predetermined force thereon, activates the first lanyard""s quick-release mechanism. In an alternate embodiment, a mechanical fitting, such as a rivet, or breakaway link or member is configured to bear the tension force and is selected to fail upon experiencing a predetermined force (e.g. 100 lbs.) thereby activating the quick release mechanism. The lanyard apparatus disclosed provides total fall protection during the transfer of a load to a structure in any elevated environment while providing an on-demand quick-release in emergency situations.
The lanyard apparatus may be used to transfer a load from the hovering aircraft to an adjacent structure by: (1) attaching the free end of the first lanyard to the helicopter; (2) attaching the free end of the second lanyard to the structure; (3) detaching the first lanyard from the helicopter; and (4) depositing the load onto the structure. When transferring from the structure to the helicopter the method is essentially reversed. When transferring loads as described, fall protection is provided since the load is safely tethered to a load bearing structure at all times, e.g. helicopter or structure. In addition, the quick release mechanism may be used to simultaneously provide an emergency release that allows the helicopter to instantly pull away without placing the external load at risk.
Accordingly, it is a primary object of the instant invention to provide an improved fall protection apparatus.
Another object of the present invention is to provide a fall protection apparatus adapted to provide comprehensive fall protection for a person or thing in an elevated environment.
Still another object of the present invention is to provide a safety apparatus that provides fall protection for a human external load engaged in an airborne transfer, before, during, and after transfer to a structure.
Yet another object of the present invention is to provide a fall protection system for HEL operations that provides an emergency release for a helicopter tethered to a structure while transferring human and non-human loads to or from the structure.
Still another object of the present invention is to provide a fall protection system for HEL operations that automatically releases a tethered helicopter in an emergency pull-away situation while transferring a load to or from the structure, while leaving the load securely tethered to the structure.
Another object of the present invention is to provide an apparatus for use in transferring loads from a hovering rotorcraft to a structure while providing total fall protection and incorporating an emergency release that does not require activation by the person being transferred.